Early evidence exists of disparities in Pre-exposure Prophylaxis (PrEP) knowledge, PrEP seeking behavior and PrEP adoption based on race. Black communities and in particular, younger Black MSM (YBMSM) have limited PrEP engagement. Evidence of few Black PrEP users is of concern with <15% of PrEP clients in Washington DC and New York City identifying as Black in PrEP demonstration/implementation projects. This finding is in the context of YBMSM leading new infections in these cities (and nationally). Furthermore, the overwhelming majority of PrEP clients nationally are privately insured and older - two characteristics incongruous with current HIV incidence. So while PrEP is promising; real-world PrEP use faces major implementation challenges. Over the past two decades, the most widely used network-based intervention for HIV prevention has been the opinion leader (OL) model or variants of it. This approach includes training popular members from a target population to promote HIV prevention messages through interpersonal communication. The effectiveness of the OL model can be limited by several factors, including: heterogeneous and overlapping networks, inadequate network assessments, and the OL's public position which often requires she/he maintain conformity to the status quo. Consequently, identifying those who connect across groups of otherwise disconnected individuals (hereafter network bridges), may be an alternative and efficient way to use network information to accelerate behavior change as has been demonstrated in other settings. This proposal moves beyond traditional OL and peer outreach models by aiming to recruit change agents based upon their structural position in a social network, in this case Facebook, in order to accelerate diffusion of PrEP. This framework is further important for measuring the potential of bridging network members as they may be the earliest innovation adopters and are likely to be more willing to challenge the existing status quo. Such bridges have structural advantages that have led to increased communication, innovation and efficiency in workplace settings; however, such bridging impact in public health contexts is understudied. We propose to address these knowledge gaps and intervene by building upon two recent studies through three phases. Phase I expands the use of Facebook for accurately characterizing a YBMSM network using a hybrid network data collection approach developed and implemented by the PI. Phase II identifies, recruits and trains change agents based upon their structural position (e.g., bridging, central, or other positions). Phase III measures and evaluates three stages of PrEP diffusion as promoted by the same agents. Our interdisciplinary team has expertise with PrEP implementation (Schneider), bridging metrics (Valente), intervention training (Bouris, Hill), social network analysis (Schneider, Valente, Goodreau), ethics (Karnik) and diffusion (Valente, Khanna). The proposed research will advance current understandings of diffusion of PrEP innovation and if successful, is structured to impact urban HIV epicenters with alarming rates of HIV infection in YBMSM.